Slurry hydrocracking processes involve the processing of a mixture of residue and fine particulate catalyst in an upflow reactor in a hydrogen-rich environment. This reaction environment facilitates very high conversion of residue to liquid products, particularly distillate boiling-range components. One example of a slurry hydrocracking process is shown in FIG. 1. Liquid feed 5 and recycle gas 10 are heated to temperature in separate heaters 15, 20 with a small portion of the recycle gas stream and the required amount of catalyst being routed through the oil heater. The outlet streams 25, 30 from both heaters 15, 20 are fed to the bottom of the slurry reactor zone 35. The reactor effluent 40 is quenched at the reactor outlet to terminate reactions and then flows to a series of separators 45, 50, 55, 60 with gas 10 being recycled back to the reactor. Liquids flow to the unit's fractionation section 65, 70 for recovery of light ends 75, naphtha 80, diesel 85, light and heavy vacuum gas oils 90, 95, and unconverted feed (pitch) 100. Heavy vacuum gas oil 105 is partially recycled to the reactor for further conversion.
Catalyst is lost during the process, and fresh catalyst makeup is required. In some processes, the fresh catalyst makeup can be up to 1 wt % or more. In addition, the processes can produce about 2-20 wt % pitch. The amount of catalyst in the pitch, and the small size of the catalyst particles, e.g., less than 1 μm, make it difficult to recover the catalyst particles using simple separation techniques.
There is a need for a process for recovering catalyst used in a slurry hydrocracking process.